Acoustic air conducting door installation for cabinet type furnace



Dec. 12, 1967 B L. DUCHiNSKY 3,357,419

ACOUSTIC AIR CONDUCTING DOOR INSTALLATION FOR CABINET TYPE FURNACE Filed 001;. 31, 1966 BERNARD L. DUCHINSKY ywmw ATTORNEY United States Patent 3,357,419 ACOUSTIC AIR CONDUCTING DOOR INSTAL- LATION FOR CABINET TYPE FURNACE Bernard L. Duchinsky, Belleville, Ill., assignor to International Oil Burner Company, St. Louis, Mo., a corporation of Missouri.

Filed Oct. 31, 1966, Ser. No. 590,622

Claims. (Cl. 126-114) The present invention relates to air conducting door installations, as used for cabinet type forced air circulation furnaces and the like. I

Heretofore louvered doors have customarily been employed in such installations, partly to provide for adequate inflow of air and partly to take advantage of the baflle-like effect of adjacent slanted louvers which, if properly arranged, prevent damage from the insertion of rigid foreign objects.

The blowers of such forced circulation furnaces and, where gun-type oil burners are used, the combustion systems thereof, generate more noise than is desirable in living rooms. When such furnaces are installed in the living rooms, as in small apartments and mobile homes, it is common practice to install pads or panels of acoustic material inside the louvers. However such acoustic material both reduces the rate of air inflow and takes up space within the cabinet at levels where such space is at a premium, for example, opposite the air impeller scroll of the circulating blower. Another disadvantage of the use of louvered furnace cabinet doors is their appearance, as they present no surfaces capable of decoration consistent with living room decor.

Objects of the present invention include providing a door installation including baffled openings adequate for the inflow of air, incorporating sound-absorbing material at the levels where it will be most effective, yet without excess bulk or thickness. Another purpose is to provide a door Whose structural strength is adequate and yet presents the ornamental appearance of spaced-apart panels whose flat forward surfaces possess suitable decorative potentialities for use in living rooms.

These and other purposes which will be apparent from this specification are provided by the present invention,

which may be generally summarized as follows:

I provide a door installation which presents a plurality of vertically arranged, solid-front acoustic panels, around whose edges are baflied inflow spaces. The rate of air flow through these spaces has unexpectedly proved to be entirely adequate.

Specifically, the present installation includes a vertically elongated rectangular door frame which includes side angular frame elements. These angular frame elements have outer flanges presented forwardly and rear flanges projecting toward each other in a plane. Fitted spacedly within the frame is a door structure made up of left and right post-like vertical members and a plurality of vertically arranged spaced-apart acoustic structural panels secured thereto, so as to provide a door having structural rigidity in the manner of a Vierendeel girder. Hinge mountings at the upper and lower ends of one of the postlike members hold the door structure within the door frame spacedly between the side angular frame elements.

'The rear flanges of the side elements provide baflling of these side spaces; while bridging strips offset rearward of the adjacent acoustic panels serve as baflies for the spaces between them. In the preferred embodiment, to be '7 described, the acoustic panels consist of metal pans se-' cured to the posts by their side edges spaced aft of ver tical-forward surfaces of the pans. Sound-absorbing material accommodated in the pans and presented inwardly,

are provided at' the levels of the principal sound generating elements of the furnace.

3,357,419 Patented Dec. 12, 1967 Referring now to the preferred embodiment shown in the accompanying drawings:

FIG. 1 is a perspective view of the front of an acoustic air conducting door installation, partly from above, broken away to show details of construction.

FIG. 2 is a perspective view, partly from the rear and below, of the door of FIG. 1.

FIG. 3 is a sectional view taken along the broken line 3-3 of FIG. 1.

FIG. 4 is an enlarged fragmentary sectional view taken along line 44 of FIG. 1.

The frame, shown in FIG. 1 and generally designated 10, is made principally of sturdy angle elements. Included are a top element 11, a bottom element 12 and left and right frame elements 13 and 14 respectively. Each frame angle element 11, 12, 13 and 14 may be considered as comprised of a forwardly presented outer flange 15 and a rear flange 16. All the rear flanges 16 project toward each other in a rearward plane designated p as shown in FIGS. 1 and 3.

The door structure generally designated 20 is vertically elongated to fit spacedly Within the frame 10. Its principal structural members are two hollow rectangular posts; referring to FIG. 1 these are a left post 21 and a right post 22. By attaching spacedly along the length of these posts 21, 22 a plurality of vertically arranged, spaced-apart acoustic structural panels, each generally designated 25, a door of adequate structural rigidity is formed, in the manner of a Vierendeel girder.

The preferred construction of the acoustic panel members 25 is shown in FIG. 3. Each metal pan 26 has a substantially vertical rectangular forward surface 27, rearwardly extending side edges 28, and top and bottom edges 29, the latter having rectangular cut-outs 30 extending over a portion only of the width of the edges 29, to permit attaching the inner surfaces of its side edges 28 to and along the outer sides of the left and right rectangular posts 21, 22. Any suitable method of securement, such as spot welding, is utilized. The portions of the side edges 28 forward of the cut-outs 30 present the pan vertical surfaces 27 sufliciently forward of the post-like members 21, 22 to give a free-floating appearance to the panels 25.

Another result is to afford maximum space within the furnace cabinet to which the present door installation is made, to accommodate bulky mechanical elements, such as the rounded scroll-type blower b, shown schematically in phantom lines in the left portion of FIG. 3. If a louvered door was here used, there would be insufficient space between it and the blower scroll b to accommodate acoustic material. However with the present construction, an adequate thickness of sound absorbing material 31, such as a low density cellular or fibrous acoustic material, is accommodated within each pan 26, secured as by an adhesive and substantially filling it except for the space occupied by the posts 21, 22. Vertically-bent return flanges 32 along the top and bottom pan edges 29, shown in FIG. 2, further secured the acoustic material 31 and also provide a freedom from sharp edges which might otherwise endanger the prying fingers of children.

From the left side of FIG. 3 it will be noted that the sound absorbing material 31 is spaced forwardly of the plane p in which the rear flange 16 of the door frame side elements 13, 14 and top and bottom elements 11, 12 project toward each other. Thus at the level of one of the acoustic panels 25 the noise-producing blower b may extend locally forward of the plane p, minimizing the overall depth required for the furnace cabinet of which the present door installation is a part.

As shown in FIG. 3, the width of the acoustic panels 13, 14, but greater than the open space between the rear flange 16 thereof. The rear flange 16 thus serves as a baflle which prevents the insertion of a rod or other rigid object into the furnace cabinet along the side and upper edges of the door, while permitting adequate air inflow as hereinafter discussed.

The acoustic panels 25 are spaced from each other vertically by spaces designated s in FIG. 2; such spaces between adjacent acoustical panels 25 provide for inflow of .airthrough the door structure. In order to similarly provide for bafiling of these spaces, bridging strips generally designated 35 are provided as .shown in FIGS. 2 and 3. The height h of each strip 35 is therefore greater than the panel spacing s. The strips 35 .are spacedly offset rearwardly of the panels 25 between the posts 21, 22, by 90 angle strip end portions 36 having narrowedtongues 37 secured to the inner sides of the posts 21, 22 between the adjacent panels 25.

The right hand post 22 is adapted for hinging the door between the top frame element 1 1 and the bottom frame element 12, preferably by the means hereafter described. The right hand post 22 projects slightly above the top edge 29 of the uppermost acoustic panel 25. Within its open upper end is pressed the square body portion 38 of a flanged hinge bushing 39. Concentric with the bore of the bushing 39 is a rivet 40 mounted through and projecting downward from the top frame member 11. The bushing 39 is preferably formed .of a material such as nylon, which assures smooth swinging operation on the rivet 40. Its construction is the same as those of the similar lower bushing 39, shown somewhat enlarged in FIG. 4.

The door 20 is spring-mounted for easy removal and to provide an upward thrust of the flange of the upper bushing 39 against the undersurface of the top frame element 11. This is achieved, as shown in the enlarged .detail view FIG. 4, by use of a similar flanged bushing 39', whose body portion 38 is pressed into the bottom end of the door post 22 which receives a vertical hinge pin 41 aligned with the rivet 40 and mounted by its countersunk head 42 in, and projecting upward from, a hinge angle bracket 43 bolted onto the forward face of the lower end of the flange 16 of the side member 13. An assembly consisting of a short compression spring 44, having cup washers 45 .on its top and bottom ends, is placed over the hinge pin 41. This presses upward against the flange of the lower post bushing 39 as the pin 41 enters the boreof this bushing 39.

When the door 20 is swung open on the hinging means so provided, a downward force will compress the spring 44, and the upper bushing 39 may be readily withdrawn downward from the rivet 40. In closed position, however, such movement is not possible. There extends closely beneath the lowest acoustic panel 25 an upward presented guard flange 47, as shown in FIG. I, mounted on the bottom frame element 12 to bar openings near the floor, as required by certain public authorities. The guard flange 47 terminates in diagonally swept-back end tabs 48 which fit into the lower ends of the left and right side angle members 13, 14 as shown in FIG. 1 and FIG. 4, providing clearance behind the hinge pin 41. The entire door frame .is preferably supported above the floor surface by a rigid Z-section horizontal support 46, welded to the undersurface of the forward presented flange of the bottom frame member '12.

The rectangular forward surfaces 27 of the acoustic panels 25, spaced forwardly of the posts 21, 22, present a floating panel appearance of separateness. Their forward surfaces 27 and edges 28, 29 may be finished decoratively by painting or adhered textured sheet material. The number and size of the panels '25 is determined so as to provide the acoustic sound absorbing filler material 31 immediately opposite each of the principal sources of furnace noise, such as the blower b. The bridging strips 35 which project inwardly of the plane p will occupy space within the furnace cabinet between these major A. noise-producing elements, where cabinet depth is usually not at a premium.

In contrast to commonly nsed louvered doors, the present door installation is especially safe for use in living rooms where small children may play. Doors possess a unique attraction for children, particularly when a source of noise lies beyond. Curious children are prone to insert their fingers into louvers and run them along the edges.

It is not feasible :to round each louver edge; many 'injuries have resulted from this. In the present invention the upper and lower pan edges 29 terminate in return flanges 32, formed by bending, which leaves these edges smooth and safe. Securement of the side edges 28 to the posts 21, 22 by spot welding just forward of the radii which leads to the surfaces of the posts, as shown in FIG. 2, leaves the side edges 28 also safe to touch. The present construction thus possesses a new degree of safety for living room furnace installations.

The inflow of air provided around the acoustic panels 25 and between them and up or down past the bridging strips 35, as shown by the arrows in FIGS. 1 and 3, has proved to be entirely adequate. The spaces provided around the acoustic panels 25 seem relatively small compared to their large rectangular forward surfaces 27; the ornamental appearance of the panels 25 is therefore enhanced. The present construction thus leaves open an adequate area for air inflow without the objectionable appearance of a louvered door, and presents the acoustic sound absorbing material 31 at the levels at which it is needed, positioned so far forwardly in the furnace cabinet as to minimize the depth required.

Modifications of the present invention will occur to those familiar with the problems of the art. Accordingly, this invention is to be construed as fully-coextensive with the claims hereof.

I claim: 1. An acoustic air conducting door installation for a cabinet type forced air circulation furnace, comprising a vertically elongated rectangular door frame having a top and bottom and including side angular frame elements having outer flanges presenting forwardly and having rear flanges projecting toward each other in a plane,

together with a vertically elongated door structure therein including left and right post-like vertical structural members,

a plurality of vertically arranged, spaced-apart acoustic structural panels secured to the left and right postlike structural members,

whereby 'to constitute with the post-like members a door having structural rigidity in the manner of a Vierendeel girder,

bridging strips characterized by a height greater than the spacing between said panels and secured to the aft side of said door structure, the greater part of thewidth of said bridging strips being spacedly offset rcarward of said panels,

whereby the spaces between the adjacent acoustic structural panels and the bridging strips provides for the inflow of air through the door structure,

the width of said acoustic panels being less than the spacing between the outer forwardly presented flanges of the rectangular door frame, and

means to hinge the upper and lower ends of one of said post-like members between the top and bottom of the door frame spacedly between said side angular f me elements,

whereby to position the .door structure with'the rear surfaces of the acoustic panels spacedly forward of the plane of the rear flanges of said door frame side elements.

thereby to provide for inflow of air between the edges of said acoustic panels and the said side frame elements.

2. An acoustic air conducting door installation as defined in claim 1, in which the acoustic panels consist of metal pans having substantially vertical rectangular forward surfaces and rearwardly-extending upper, lower and side edges, together with sound-absorbing material accommodated within said pans and presented inwardly toward and spacedly forward of the plane in which the rear flanges of the door frame side elements project toward each other. 3. An acoustic air conducting door installation as defined in claim 2, in which the acoustic panels are secured to the post-like memhere by attachment thereto of portions of their side edges spacedly aft of their vertical forward surfaces, whereby said vertical forward surfaces are presented forward of the post-like members to provide maximum space inward of said panels and give the ornamental appearance of separateness thereto.

4. An acoustic air conducting door installation as defined in claim 3, in which the means to hinge the said post-like member includes a compression spring at one end thereof and a pin 5 and socket provision at the other end thereof, whereby the door is rendered readily removable. 5. An acoustic air conducting door installation as defined in claim 3, in which upper and lower edges of the metal pans of said acoustic panels terminate in reverse flanges inwardly of the sound-absorbing maten'al therein, whereby the sound-absorbing material is more securely retained and the spaces between adjacent panels are rendered safe to prying hands.

15 References Cited UNITED STATES PATENTS 2,546,674 3/1951 Milhouse llO-175 20 JAMES W. WESTHAVER, Primary Examiner. 

1. AN ACOUSTIC AIR CONDUCTING DOOR INSTALLATION FOR A CABINET TYPE FORCED AIR CIRCULATION FURNACE, COMPRISING A VERTICALLY ELONGATED RECTANGULAR DOOR FRAME HAVING A TOP AND BOTTOM AND INCLUDING SIDE ANGULAR FRAME ELEMENTS HAVING OUTER FLANGES PRESENTING FORWARDLY AND HAVING REAR FLANGES PROJECTING TOWARD EACH OTHER IN A PLANE, TOGETHER WITH A VERTICALLY ELONGATED DOOR STRUCTURE THEREIN INCLUDING LEFT AND RIGHT POST-LIKE VERTICAL STRUCTURAL MEMBERS, A PLURALITY OF VERTICALLY ARRANGED, SPACED-APART ACOUSTIC STRUCTURAL PANELS SECURED TO THE LEFT AND RIGHT POSTLIKE STRUCTURAL MEMBERS, WHEREBY TO CONSTITUTE WITH THE POST-LIKE MEMBERS A DOOR HAVING STRUCTURAL RIGIDITY IN THE MANNER OF A VIERENDEEL GIRDER, BRIDGING STRIPS CHARACTERIZED BY A HEIGHT GREATER THAN THE SPACING BETWEEN SAID PANELS AND SECURED TO THE AFT SIDE OF SAID DOOR STRUCTURE, THE GREATER PART OF THE WIDTH OF SAID BRIDGING STRIPS BEING SPACEDLY OFFSET REARWARDLY OF SAID PANELS, WHEREBY THE SPACES BETWEN THE ADJACENT ACOUSTIC STRUCTURAL PANELS AND THE BRIDGING STRIPS PROVIDES FOR THE INFLOW OF AIR THROUGH THE DOOR STRUCTURE, THE WIDTH OF SAID ACOUSTIC PANELS BEING LESS THAN THE SPACING BETWEEN THE OUTER FORWARDLY PRESENTED FLANGES OF THE RECTANGULAR DOOR FRAME, AND 